Plug and socket connectors with flexible bushings



April 27, 1965 R. F. OXLEY 3,181,104

PLUG AND SOCKET CONNECTORS WITH FLEXIBLE BUSHINGS Filed Nov. 26, 1962 2 Sheets-Sheet 1 Ronan-r F OxLEY R. F. OXLEY April 27, 1965 PLUG AND SOCKET CONNECTORS WITH FLEXIBLE BUSHINGS 2 Sheets-Sheet 2 Filed Nov. 26, 1962 ATTORNEY INvEN-roz ROBERT F'. OKLEY United States Patent O 3,181,104 PLUG AND SOCKET CONNECTORS WITH FLEXIBLE BUSHINGS Robert Frederick xley, Priory Park, Ulverston, England Filed Nov. 26, 1962, Ser. No.`24il,lll9 Claims priority, application Great Britain, Nov. 27, 1961,

42,37 1/ 61 8 Claims. (Cl. 339-59) This invention relates to plug and socket electrical connectors and to fittings for attachment to the plug body or socket body to provide the individual contact pins of such a connector.

Unless the contact pins of an electrical plug and socket connector are accurately positioned in the plug and socket bodies so that the individual plug pins and socket pins are accurately aligned with one another when the two parts of the connector are joined, a considerable force willy be required to connect and kdisconnect the plug and socket. This is particularly the case where the connector has pins for connecting a large number of ways, for example of the order of fty or a hundred ways,

where any substantial degree of misalignment may result in the plug and socket being almost inseparable by hand.

It will be apparent that if the pins are rigidly secured only the most accurate alignment will be satisfactory. Slightly less accuracy may be tolerated where the pins are resiliently mounted as in the case in some forms of connector in which the pins are mounted in a rubber block.` However, even with such resilient mounting, separation forces will become intolerably large if there is more than the slightest amount of misalignment and resilient mounting gives rise to its own problems. Cornconstruction of plug and socket connector which permits ease of manufacture, particularly of non-standard items required in small numbers, and yet has an acceptable separation force.

According to one aspect of the present invention a plug or a socket of a multi-way electrical plug and socket connector includes a body member having apertures therein and a number of fittings supported in the apertures, each fitting comprising a bushing of resiliently deformable insulating material, preferably polytetraiuoroethylene (Teflon), having a circumferential groove on its external surface and a pin forced into the bore of the bushing and retained therein, the pin being formed as a plug contact or as a socket contact and edges of the aperture being received in the groove in the bushing so as to retain the bushing on the body member with limited freedom of lateral movement.

The invention also includes, according to another aspect, the fittings themselves.

It will be readily appreciated that a non-standard plug or socket can easily be made from a suitable body member and the requisite number of fittings by drilling apertures in the body member where required and fastening a fitting in each aperture. A high degree of accuracy in positioning the apertures is not required since the limited freedom of lateral movement afforded to each fitting will 3,l8l,l@4 Patented Apr. 27, 1965 the permanent structure of a piece of equipment and the plug be formed on the chassis of a removable complex of electrical components, for example a printed circuit board, which can be readily removed and replaced by another identical or different complex.

In many cases it will not be necessary for both the plug and socket to have pins having freedom of lateral movement. Also it will not always be necessary for every pair of plug and socket pins to have one of the pins with freedom of lateral movement; a few pairs of which both pins are rigidly fixed to the respective bodies may, in some cases, be desirable to prevent relative movement between the bodies.

A number of preferred features of the bushing and pin will now be described. The pin may be constructed at one end as a socket contact and at the other end as a plug contact which will fit the socket of an identical pin. In this way only one form of pin is necessary to construct both plugs and sockets.

One end of the bushing may be tapered so that its diameter increases from one end of the bushing to the circumferential groove. Thus the bushing may be pushed into an aperture which is of greater diameter than the bushing at the thin end of the taper and at the groove but of smaller diameter than the thick end of the taper, the resilience of the material of the bushing permitting the bushing to be forced into the aperture until the edges of the aperture are located within the groove.

Preferably the pin has an enlargement, which may be wedge-shaped or barb-like, which is bigger than the bore of the bushing and which can be forced into the bore of the bushing until the enlargement lies beyond the aperture and expands the projecting end of the bushing. With this construction the circumferential wall of the groove may be tapered. When the pin is forced into the bushing, the enlargement will expand the projecting end of the bushing and this will result in the circumferential Wall of the groove becoming parallel with the axis of the bushing.

The invention may be performed in Various ways but some embodiments will now be described by way of example with reference to the accompanying drawings, in which: t g

FIGURE 1 is a somewhat diagrammatic longitudinal section on the line I-l of FIGURE 2, through a plug and socket connector, both parts being at the ends of flexible cables;

FIGURE Q. is a transverse section through the plug taken on the line II-II of FIGURE 1; i

FIGURE 3 shows the components of single fitting before assembly;

FIGURE 4 shows the components shown in FIGURE 3 after assembly; and

FIGURE 5 is a longitudinal section through a socket forming part of the chassis of a piece of electrical equipment and a modified plug carried at the end of a flexible cable, only the socket being constructed in accordance with the principles of the invention.

Referring now to the drawings, the plug and socket connector shown in FIGURES 1 and 2 consists of a 2 and a socket 3 carried at the end of a multi-core flexisuertesble cable d, rthe plug ll includes a contact-carrying body kmember 5 consisting of a generally rectangular metal plate and a box-likel rectangular metal cover member 6. The cover member has an ear '7 projecting inwardly from each corner and the body member 5 rests against the ears and is secured to them by screws S. The side Walls' of the cover member 6 extend below the body member 5 to form a skirt 9. The top of the cover member d has a centralaperture through which the cable 2 enters the plug, the cable being held by gripping lmeans ll.

rThe socket member similarly includes a contact-carrying body member l?. and a cover member 13, the cover member having ears lid to which the body member 12 is secured by screws l5. Thermulti-core cable i enters the socket through a central aperture inthe cover member i3 and is gripped by means ld. The cover member 13 extends above the body member l2 to form a skirt 17 which is a snug it within the skirt 9 of the plug l. The

body member 5 of the plug carries a locating peg i8 and a locating socket i9 which mate with a locating socket 21 and a locating peg 22 carried by the body member 12 of the socket. These locating pegs and sockets prevent the plug and socket being reversed end for end with respect to one another. v Y

vThe connector being described is able to connect titty Vways and the body members 5 and l2 each contain titty apertures arranged in six -rowsoflive apertures alternating with live rows of four apertures. `Each aperture vcontains a iitting of the construction shown in detail in FIGURES 3 and 4 in which Vthe apertured member A represents the body member 5 of the plug or the body member l2 of the socket. Each fitting consists of a bushing 3l of Teiion and a metal pin 32..v rlhe bushing has a cylindrical part 33 of a diameter which is too great to pass through the aperture 3d in the member A, a groove 35 whose circumferential wall is tapered, the thicker end being adjacent the cylindrical part 33 and having a diameterless than that of the aperture 34, and a tapered end part 36. The thick end of theend part 3d is adjacent the vgroove 35 and will just pass through the aperture 3d. Y

The bushing has a coaxial borel 37 extending through it, the bore widening out at one end to form a sloping linternal shoulder 33. The pin 32 has a flange v39 at one end, the underside of the flange being inclined toV the axis of the pin to correspond with the sloping shoulder 33 in the'bore 37 of the bushing. The pin also has a wedge-shaped enlargement il which has, at its thickest part, a diameter which is somewhat greater than that of the bore 37', and an intermediate portion 4i-2 Whose diameter is very slightly greater than that of the bore 37. Beyond theenlargement di is'an end portion 43 which is of slightly smaller diameter. Thepin is counterbored from the end having the flange 39 to form a socket 44 having a bell-shaped mouth. The Wall of the socket is split in a number of places.

To mount the fitting on the body member A, the

bushing is irst passed through the aperture until the underside of the cylindrical part 33 engages the body member around the aperture. The pinjis then forced into the bore 37 lin the bushing until the flange 39 engages the shoulder 38 at which time the enlargement il will `lie within the end part 36 of the bushing and will expand this end part so that it will no longerpass through the aperture. The expansion of the end part 36 will cause the previously tapered circumferential wall of the groove 35 to become cylindrical but the diameter of the circumferential wall of the groove will still be less than that Vot the aperture. Thus the fitting is securely fastened to the body member but has limited amount of freedom of lateral movement, the'amount of movement in any direction being the difference in diameters of the circumferential Wall of the groove andthe aperture. The cylindrical part i'will Vgrip the wall of the socket 4d and will tend to slightly. close its mouth sothat it will firmly grip a plug entered into it. j

y The iitting may provide an individual plug contact or an individual socket contact depending upon which way it is mounted. The iittings are mounted on the body member 5 of the plug llwith their end portions 43 projecting below the body member. The sockets 44 of the pins of the plug form solder wells inrwhich the individual conductors of the cable 2 are secured;VV The iittings are mounted on the body member 12 of the socket 3 with the sockets 44 of the pins above the body member and the individual conductors of the cable 4 are soldered to the end portions i3 of Vthe pins.

When the plug l and the socketZ are brought together,

.- the 'end portions d3 of the pins of the plug enter the sockets de or the pins of the socket. Since all the pins have freedom of lateral movement the pins can adjust their positions until they are coaxial, this movement ,being facilitated by the bell-shaped'mouths of the sockets d4. For this reason the apertures in the body members 5 and l2 do not have to be located with a high Vdegree of accuracy.

In the embodiment shown in'FIGURE 5 the plug is not constructed in accordance with the present invention, the pins being resiliently secured but without freedom lof lateral movement.V The plug consists of atbody 5l Vof resilient material having a number of bores arranged inrows perpendicular to the plane in which they areV viewed in FIGURE 5. Bach bore contains a pin 52 which has an upper portion 53 formed as a numberfof barbs, a flange 54 and a plug portion 55. The barbed end of the pin is forced into a bore in the body 51 until the ange'Sd abuts the body. The barbed end of each pinis formed as a solder wellin which is secured one of the conductors of a multi-core cable 56..

The plug mates with a socket constructed -in accordance with the principles of the invention and consisting of a number of ittings 57 of the construction shown in FlGURES 3 and 4 mounted in apertures in the chassis 58 of a piece of electrical equipment. The sockets-of the fittings on the chassis 5S have limited freedom of lateral movement to enable themto align themselves with the Vpins of the plug.

'What l claim as my invention and desire to secure by lying on the other side of said body and an intermediate portion between said head portion andsaid end portion,

said head portion and said end portion having diameters greater vthan said apertures and less than the spacing between the centers of adjacent apertures and said inter- Vmediate portion having, when said pin extends through said bore, a diameter' less than said apertures to secure *movement 2. An electrical socket assembly comprising a sheet metal socket body having a plurality of apertures/extending through it and a fitting secured in each aperture, each fitting consisting of a metal pin, one end of said pin being formed Vas a socket, and a bushing of resiliently deformable insulating material and having a bore, said pin extending through and being retained in said bore, a head portion lying on one side of saidbody, an end portion lying on the other side of said body and an intermediate porr tion between said head portion and said end portion,said head portion being oa diameter such that it cannot pass through the aperture, said end portion being of a diameter such that it can pass through the aperture, before said said bushing to said body with limited freedom of lateral tion lying on one side of said body,

pin extends through said bore and said intermediate portion being of a diameter less than the aperture to form a groove receiving the portions ot said body member surrounding the aperture with clearance between said intermediate portion and said surrounding portions, and a metal pin extending through when said pin extends through said bore, said pin having a portion of a size greater than the bore of said bushing but which can be forced through said bore, said portion lying within said end portion of said bushing and expanding said end portion to a diameter greater than the aperture to secure said bushing to said body with limited freedom of lateral movement, the diameter of said head portion of said bushing and the diameter of said expanded end portion of said bushing being less than the spacing between the centers of adjacent apertures.

3. An electrical socket assembly comprising a sheet metal socket body having a plurality of apertures extending through it and a fitting secured in each aperture, each tting consisting of a metal pin, one end of said pin being formed as a socket,.and a bushing of resiliently deformable insulating material and having a bore, said pin extending through and being retained in said bore, a head portion lying on one side of said body, an end portion lyinrr on the other side of said body and an intermediate portion between said head portion and said end portion, said head portion being of a diameter such that it cannot pass through the aperture, said end portion being of a diameter such that it can pass through the aperture, before said pin extends through said bore and said intermediate portion being tapered in its unstressed condition, its greatest diameter being adjacent said head portion and being less than the diameter of the aperture, said intermediate portion forming a circumferential groove receiving the portions of said body member immediately adjacent the aperture, said pin having a portion of a size greater than the bore of said bushing but which can be forced through said bore, said portion lying within said end portion of Isaid bushing and expanding said end portion to a diameter greater than the aperture and deforming said intermediate portion into a cylindrical condition whose external diameter is less than the internal diameter of the aperture to secure said bushing to said body with limited freedom of lateral movement, the diameter of said head portion of said bushing and the diameter of said expanded end portion of said bushing being less than the spacing between the centers of adjacent apertures.

4. An electrical plug assembly comprising a sheet metal plug body having a plurality of apertures extending through it and a tting secured in each aperture, each tting consisting of a metal pin, one end of said pin being formed as a plugand a bushing of resiliently deformable insulating material and having a bore, said pin extending through and being retained in said bore, a head poran end portion lying on the other side of said body and an intermediate portion between said head portion and said end portion, said head portion and said end portion having diameters greater than said apertures and less than the spacing between the centers of adjacent apertures and said intermediate portion having, when said pin extends through said bore, a diameter less than said apertures to secure said bushing to said body with limited freedom of lateral movement.

5. One part of a two-part plug and socket connector including a body member having a plurality of apertures extending through it, and a plurality of contact ittings, each tting being secured in one of said apertures in said body member and comprising a metal pin, one end of said pin being formed as a contact member of said one part of a two-part plug and socket connector, and a bushing of resilient insulating material having a bore, through which said pin extends and in which said metal pin is retained, and an external circumferential groove, the portions of said body member surrounding the respective aperture being received in said groove to secure said bushing to said body member, the diameter of said bushing at said groove when said pin extends through said bore being less than the diameter of said aperture to permit limited freedom of lateral movement to said bushing and the diameters of adjacent bushings being smaller than the spacing between the centers of adjacent apertures.

6. One part of a two part plug and socket connector according to claim 5 in which said one end of said pin is formed as a socket contact.

7. One part of a two part plug and socket connector according to claim 5 in which said one end of said pin is formed as a plug contact.

8. A. plug and socket connector comprising cooperating plug and socket members, each said member including a thin iiat body member having a plurality of apertures extending through it, a cover member secured to said body member, entry means in said cover member for a multi-core ilexible cable, and a plurality of contact fittings, each fitting being secured in one of said apertures and comprising a bushing having a bore, and a metal pin extending through and retained in said bore, said bushing being of resiliently deformable insulating material and having a head portion, an end portion and an intermediate portion, said head portion and said end portion lying on opposite sides of said body member and having diameters greater than said one aperture and less than the distance between the center of said one aperture and the centers of adjacent apertures, said end portion lying on the other side of said body member and said intermediate portion having a diameter less than said head portion and said end portion and said aperture to form a circumferential groove, the edges of said aperture being received in said groove with clearance between said intermediate portion and said edgesto permit limited freedom of lateral movement of the bushing relative to the body when said pin extends through said bore, said pin having a portion lying within said end portion and expanding said end portion to a diameter greater than said aperture, one end of said pin being formed to receive in plug and socket relationship one end of a corresponding pin of the other said member.

Rel-'cremes Cited by the Examiner UNITED STATES PATENTS 1,680,940 8/28 Emmons. 1,697,814 1/29 Forbes. 2,674,645 4/54 Fine. 2,809,362 10/ 57 Powell 339-64 X 2,911,460 11/59 Oxley 174-153 2,926,210 2/60 Sturges. 2,948,773 8/60 Hawes 339-126 X 3,086,074 4/63 Just et al. 174-153 X FOREIGN PATENTS 885, 876 12/ 61 Great Britain.

OTHER REFERENCES Lawson, A. A.: Electrical Mfg., October 1954, page 135.

DONLEY J. STOCKING, Primary Examiner. JOSEPH D. SEERS, ALFRED S. TRASK, Examiners. 

1. AN ELECTRICAL SOCKET ASSEMBLY COMPRISING A SHEET METAL SOCKET BODY HAVING A PLURALITY OF APERTURES EXTENDING THROUGH IT AND A FITTING SECURED IN EACH APERTURE, EACH FITTING CONSISTING OF A METAL PIN, ONE END OF SAID PIN BEING FORMED AS A SOCKET, AND A BUSHING OF RESILIENTLY DEFORMABLE INSULATING MATERIAL AND HAVING A BORE, SAID PIN EXTENDING THROUGH AND BEING RETAINED IN SAID BORE, A HEAD PORTION LYING ON SIDE OF SAID BODY, AN END PORTION LYING ON THE OTHER SIDE OF SAID BODY AND AN INTERMEDIATE PORTION BETWEEN SAID HEAD PORTION AND SAID END PORTION SAID HEAD PORTION AND SAID END PORTION HAVING DIAMETERS GREATER THAN SAID APERTURE AND LESS THAN THE SPACING BETWEEN THE CENTERS OF ADJACENT APERTURES AND SAID INTERMEDIATE PORTION HAVING, WHEN SAID PIN EXTENDS THROUGH SAID BORE, A DIAMETER LESS THAN SAID APERTURES TO SECURE SAID BUSHING TO SAID BODY WITH LIMITED FREEDOM OF LATERAL MOVEMENT. 